FR: make circular available in nix-bitcoin

[swissrouting]

The nix-bitcoin project provides a NixOS-compatible package of Bitcoin tools that can be deployed in an easily-reproducible way.

I'd love to use circular with nix-bitcoin. There are already a bunch of CLN plugins published in that repo. I think all it would take to make circular available too is to write a nix wrapper file, similar to what's already present for those other plugins.

Example: https://github.com/fort-nix/nix-bitcoin/blob/master/modules/clightning-plugins/feeadjuster.nix